GM Service Manual Online
For 1990-2009 cars only

Step

Action

Value(s)

Yes

No

Important: Check for inoperative bulb before beginning diagnostic procedure.

1

Did you perform the Lighting Diagnostic System Check?

--

Go to Step 2

Go to Diagnostic System Check - Lighting Systems

2

  1. Disconnect C201.
  2. With DMM, check for continuity in CKT 1201 (DK BLU) between cavity C of both headlamps and cavity E12 of C201.

Is continuity present?

--

Go to Step 4

Go to Step 3

3

Locate and repair OPEN in CKT 1201 (DK BLU).

Is the repair complete?

--

Go to Step 11

--

4

With DMM, check for continuity in cavity E12 and cavity E13 of C201 (steering column side of connector).

Is continuity present?

--

Go to Step 8

Go to Step 5

5

Check for an OPEN in the following two CKT's located in the steering column harness.

    • CKT 1201 (TAN) between cavity E12 and the steering column multi-function switch.
    • CKT 544 (LT BLU) between cavity E13 and the steering column multi-function switch.

Did you find an OPEN?

--

Go to Step 7

Go to Step 6

6

Replace the steering column multi-function switch. Refer to Multifunction, Turn Signal, and Hazard Switch Replacement - On Vehicle .

Is the repair complete?

--

Go to Step 11

--

7

Repair the OPEN of the faulty CKT.

Is the repair complete?

--

Go to Step 11

--

8

  1. Remove DRL relay.
  2. Check for continuity of pins 87A and 30 of the DRL relay.

Is continuity present?

--

Go to Step 10

Go to Step 9

9

Replace the DRL relay.

Is the repair complete?

--

Go to Step 11

--

10

Locate and repair OPEN in one of the following two CKT's:

    • CKT 544 (PPL) between C201 and the DRL relay (located in relay center #2).
    • CKT 750 (BLK) between the DRL relay and ground G110.

Is the repair complete?

--

Go to Step 11

--

11

Operate the system in order to verify the repair.

Did you correct the condition?

--

System OK

Go to Step 2